Polyoxyalkylene polyether monool polyurethane foam additive

ABSTRACT

There is now provided a polyol composition containing a polyol having polyester linkages, an aliphatic or cycloaliphatic C 4  -C 7  hydrocarbon blowing agent, and a polyoxyalkylene polyether monool initiated with a C 8  -C 24  fatty hydrocarbon having one alkylene oxide active hydrogen atom. We have found that the monool emulsifies the C 4  -C 7  blowing agent in the compound having polyester linkages, to form an emulsified polyol composition, after which an organic aromatic isocyanate may be reacted with the emulsified polyol composition to form a closed cell polyurethane foam. 
     The polyol composition is used to make rigid closed cell polyisocyanate based foams which are dimensionally stable, and have good insulation values and flame retardance. Combining the monool with the polyester based polyol produces a foam having a density lower than that of a reference foam made with the same ingredients and amounts except in the absence of the monool. Whether the monool is merely mixed with the polyol or used to form an emulsion with the hydrocarbon blowing agent and the polyol, the foam density may be lowered when the monool is used.

FIELD OF THE INVENTION

The present invention relates to rigid closed cell polyisocyanate basedfoams and to polyol compositions used to make such foams. In particular,the invention relates to polyisocyanate based foams and polyolcompositions used to make the foams, containing a polyol havingpolyester linkages, a polyoxyalkylene polyether monool, and a C₄ -C₇hydrocarbon blowing agent.

BACKGROUND OF THE INVENTION

Hydrocarbon blowing agents such as pentane and cyclopentane areconsidered viable alternatives to the traditional CFC's in the rigidfoam insulation sector. A publication by H. Ballhaus et al. entitled"Hydrocarbons Provide Zero ODP and Zero GWP Insulation for HouseholdRefrigeration," in Polyurethanes World Congress 1993, Oct. 10-13, 1993,pages 33-39, describes a foaming apparatus adapted for use with thevolatile hydrocarbon blowing agents. As can be seen from the descriptionin this publication, the hydrocarbon is separately metered into the mixhead, or fed into a day tank which is kept under constant agitation.Many of the insulation foams use polyester polyols as the base polyol.The hydrocarbons have only a limited or no solubility in most polyesterpolyols. To avoid phase separation, the hydrocarbon blowing agent musteither be metered into a high pressure mix head, or fed into the daytank under agitation to keep the hydrocarbon mixed with the polyol.

Therefore, we found it desirable to find a chemical agent which wouldkeep hydrocarbon blowing agents dispersed throughout the polyol in theabsence of agitation, either in the form of an emulsion, a suspension,or homogeneously solubilized. The chemical agent chosen, however, shouldnot sacrifice the mechanical properties of an equivalent foam made inthe absence of the chemical agent, in particular, the k-factor, theflammability, the compressive strength, and the dimensional stability ofthe foam.

SUMMARY OF THE INVENTION

There is now provided a polyol composition containing a polyol havingpolyester linkages, an aliphatic or cycloaliphatic C₄ -C₇ hydrocarbonblowing agent, and a polyoxyalkylene polyether monool initiated with aC₈ -C₂₄ fatty hydrocarbon having one alkylene oxide active hydrogenatom. We have found that the C₄ -C₇ blowing agent is emulsified with thecompound having polyester linkages by mixing with the monool to form anemulsified polyol composition, after which the organic aromaticisocyanate is reacted with the emulsified polyol composition.

The polyol composition is used to make rigid closed cell polyisocyanatebased foams which are dimensionally stable, and have good insulationvalues and flame retardance. An unexpected advantage of mixing themonool with the polyols, however, was that the density of the resultingfoam was lower than reference foams made with the same ingredients andmounts except in the absence of the monool. In one embodiment, thedensity of the foam made with the monool was at least 2.00% less thanreference foams made with the same ingredients and amounts except in theabsence of the monool. Further, it is not necessary to emulsify theblowing agent in the polyol first to experience this advantage. Thus,one has the option of using the monool to both emulsify the hydrocarbonblowing agent in the polyol and lower the density of the foam, or merelymix the monool with the polyol and separately meter the hydrocarbonblowing agent into the mix head and thereby also lower the density ofthe resulting foam.

There is also provided a method for making a rigid closed cellpolyisocyanate based foam and the foam thereof, by reacting an organicaromatic polyisocyanate and a polyol composition in the presence of a C₄-C₇ aliphatic or cycloaliphatic hydrocarbon blowing agent, where thepolyol composition comprises a compound having polyester linkages, and apolyoxyalkylene polyether monool initiated with a C₈ -C₂₄ fattyhydrocarbon having one alkylene oxide active hydrogen atom. Thehydrocarbon blowing agent may be emulsified with the polyol by using themonool, or the polyisocyanate may be reacted with the polyol compositionin the presence of the hydrocarbon blowing agent without first formingan emulsion.

DETAILED DESCRIPTION OF THE INVENTION

As the first ingredient in the polyol composition, there is provided ana) polyol having polyester linkages. Preferably, The polyols have afunctionality of 1.8 to 8, preferably 3 to 8, and an average hydroxylnumber of 150 to 850, more preferably 350 to 800. Polyols havinghydroxyl numbers outside this range may be used, but it is preferredthat the average hydroxyl number for the total amount of polyols usedfall within the range of 150 to 850.

Other types of polyols may be used in combination with the polyol havingpolyester linkages. Examples of polyols are thioether polyols, polyesteramides and polyacetals containing hydroxyl groups, aliphaticpolycarbonates containing hydroxyl groups, amine terminatedpolyoxyalkylene polyethers, and preferably, polyester polyols, polyesterpolyether polyols, polyoxyalkylene polyether polyols, and graftdispersion polyols. Mixtures of at least two of the aforesaid polyolscan be used as long as the combination has an average hydroxyl number inthe aforesaid range.

The terms "polyol having polyester linkages" and "polyester polyol" asused in this specification and claims includes any minor amounts ofunreacted polyol remaining after the preparation of the polyester polyoland/or unesterified low molecular weight polyols (e.g., glycol) addedafter the preparation of the polyester polyol. The polyester polyol caninclude up to about 40 weight percent free glycol.

Polyols having polyester linkages broadly include any polyol having twoor more ester linkages in the compound, such as the conventionalpolyester polyols and the polyester-polyether polyols.

The polyester polyols advantageously have an average functionality ofabout 1.8 to 8, preferably about 1.8 to 5, and more preferably about 2to 3. Their average hydroxyl number values generally fall within a rangeof about 15 to 750, preferably about 30 to 550, and more preferablyabout 150 to 500 (taking into account the free glycols that may bepresent), and their free glycol content generally is from about 0 to 40weight percent, and usually from 2 to 15 weight percent, of the totalpolyester polyol component.

Suitable polyester polyols can be produced, for example, from organicdicarboxylic acids with 2 to 12 carbons, preferably aliphaticdicarboxylic acids with 4 to 6 carbons, and multivalent alcohols,preferably diols, with 2 to 12 carbons, preferably 2 to 6 carbons.Examples of dicarboxylic acids include succinic acid, glutaric acid,adipic acid, suberic acid, azelaic acid, sebacic acid,decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid,isophthalic acid, and terephthalic acid. The dicarboxylic acids can beused individually or in mixtures. Instead of the free dicarboxylicacids, the corresponding dicarboxylic acid derivatives may also be usedsuch as dicarboxylic acid mono- or di-esters of alcohols with 1 to 4carbons, or dicarboxylic acid anhydrides. Dicarboxylic acid mixtures ofsuccinic acid, glutaric acid and adipic acid in quantity ratios of20-35:35-50:20-32 parts by weight are preferred, especially adipic acid.Examples of divalent and multivalent alcohols, especially diols, includeethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropyleneglycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,1,10-decanediol, glycerine and trimethylolpropanes, tripropylene glycol,tetraethylene glycol, tetrapropylene glycol, tetramethylene glycol,1,4-cyclohexane-dimethanol, ethanediol, diethylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or mixtures of at leasttwo of these diols are preferred, especially mixtures of 1,4-butanediol,1,5-pentanediol, and 1,6-hexanediol. Furthermore, polyester polyols oflactones, e.g., ε-caprolactone or hydroxycarboxylic acids, e.g.,ω-hydroxycaproic acid, may also be used.

The polyester polyols can be produced by polycondensation of organicpolycarboxylic acids, e.g., aromatic or preferably aliphaticpolycarboxylic acids and/or derivatives thereof and multivalent alcoholsin the absence of catalysts or preferably in the presence ofesterification catalysts, preferably in an atmosphere of inert gases,e.g., nitrogen, carbon dioxide, helium, argon, etc., in the melt attemperatures of 150° to 250° C., preferably 180° to 220° C., optionallyunder reduced pressure, up to the desired acid value which is preferablyless than 10, especially less than 2. In a preferred embodiment, theesterification mixture is subjected to polycondensation at thetemperatures mentioned above up to an acid value of 80 to 30, preferably40 to 30, under normal pressure, and then under a pressure of less than500 mbar, preferably 50 to 150 mbar. The reaction can be carried out asa batch process or continuously. When present, excess glycol can bedistilled from the reaction mixture during and/or after the reaction,such as in the preparation of low free glycol-containing polyesterpolyols usable in the present invention. Examples of suitableesterification catalysts include iron, cadmium, cobalt, lead, zinc,antimony, magnesium, titanium and tin catalysts in the form of metals,metal oxides or metal salts. However, the polycondensation may also bepreformed in liquid phase in the presence of diluents and/orchlorobenzene for aziotropic distillation of the water of condensation.

To produce the polyester polyols, the organic polycarboxylic acidsand/or derivatives thereof and multivalent alcohols are preferablypolycondensed in a mole ratio of 1:1-1.8, more preferably 1:1.05-1.2.

After transesterification or esterification, the reaction product can bereacted with an alkylene oxide to form a polyester polyol mixture. Thisreaction desirably is catalyzed. The temperature of this process shouldbe from about 80° to 170° C., and the pressure should generally rangefrom about 1 to 40 atmospheres.

While the aromatic polyester polyols can be prepared from substantiallypure reactant materials, more complex ingredients are advantageouslyused, such as the side stream, waste or scrap residues from themanufacture of phthalic acid, terephthalic acid, dimethyl terephthalate,polyethylene terephthalate, and the like. Particularly suitablecompositions containing phthalic acid residues for use in the inventionare (a) ester-containing byproducts from the manufacture of dimethylterephthalate, (b) scrap polyalkylene terephthalates, (c) phthalicanhydride, (d) residues from the manufacture of phthalic acid orphthalic anhydride, (e) terephthalic acid, (f) residues from themanufacture of terephthalic acid, (g) isophthalic acid, (h) trimelliticanhydride, and (i) combinations thereof. These compositions may beconverted by reaction with the polyols of the invention to polyesterpolyols through conventional transesterification or esterificationprocedures.

Polyester polyols whose acid component advantageously comprises at leastabout 30 percent by weight of phthalic acid residues are useful. Byphthalic acid residue is meant the group: ##STR1##

A preferred polycarboxylic acid component for use in the preparation ofthe aromatic polyester polyols is phthalic anhydride. This component canbe replaced by phthalic acid or a phthalic anhydride bottomscomposition, a phthalic anhydride crude composition, or a phthalicanhydride light ends composition, as such compositions are defined inU.S. Pat. No. 4,529,744.

Other preferred materials containing phthalic acid residues arepolyalkylene terephthalates, especially polyethylene terephthalate(PET), residues or scraps.

Still other preferred residues are DMT process residues, which are wasteor scrap residues from the manufacture of dimethyl terephthalate (DMT).The term "DMT process residue" refers to the purged residue which isobtained during the manufacture of DMT in which p-xylene is convenedthrough oxidation and esterification with methanol to the desiredproduct in a reaction mixture along with a complex mixture ofbyproducts. The desired DMT and the volatile methyl p-toluate byproductare removed from the reaction mixture by distillation leaving a residue.The DMT and methyl p-toluate are separated, the DMT is recovered andmethyl p-toluate is recycled for oxidation. The residue which remainscan be directly purged from the process or a portion of the residue canbe recycled for oxidation and the remainder diverted from the processor, if desired, the residue can be processed further as, for example, bydistillation, heat treatment and/or methanolysis to recover usefulconstituents which might otherwise be lost, prior to purging the residuefrom the system. The residue which is finally purged from the process,either with or without additional processing, is herein called DMTprocess residue.

These DMT process residues may contain DMT, substituted benzenes,polycarbomethoxy diphenyls, benzyl esters of the toluate family,dicarbomethoxy fluorenone, carbomethoxy benzocoumarins and carbomethoxypolyphenols. Cape Industries, Inc. sells DMT process residues under thetrademark Terate® 101. DMT process residues having a differentcomposition but still containing the aromatic esters and acids are alsosold by DuPont and others. The DMT process residues to betransesterified in accordance with the present invention preferably havea functionality at least slightly greater than 2. Such suitable residuesinclude those disclosed in U.S. Pat. Nos. 3,647,759; 4,411,949;4,714,717; and 4,897,429; the disclosures of which with respect to theresidues are hereby incorporated by reference.

Examples of suitable polyester polyols are those derived from PET scrapand available under the designation Chardol 170, 336A, 560, 570, 571 and572 from Chardonol and Freol 30-2150 from Freeman Chemical. Examples ofsuitable DMT derived polyester polyols are Terate® 202, 203, 204, 254,2541, and 254A polyols, which are available from Cape Industries.Phthalic anhydride derived polyester polyols are commercially availableunder the designation Pluracol® polyol 9118 from BASF Corporation, andStepanol PS-2002, PS-2402, PS-2502A, PS-2502, PS-2522, PS-2852,PS-2852E, PS-2552, and PS-3152 from Stepan Company.

Polyoxyalkylene polyether polyols, which can be obtained by knownmethods, can be mixed with the polyol having polyester linkages. Forexample, polyether polyols can be produced by anionic polymerizationwith alkali hydroxides such as sodium hydroxide or potassium hydroxideor alkali alcoholates, such as sodium methylate, sodium ethylate, orpotassium ethylate or potassium isopropylate as catalysts and with theaddition of at least one initiator molecule containing 2 to 8,preferably 3 to 8, reactive hydrogens or by cationic polymerization withLewis acids such as antimony pentachloride, boron trifluoride etherate,etc., or bleaching earth as catalysts from one or more alkylene oxideswith 2 to 4 carbons in the alkylene radical. Any suitable alkylene oxidemay be used such as 1,3-propylene oxide, 1,2- and 2,3-butylene oxide,amylene oxides, styrene oxide, and preferably ethylene oxide and1,2-propylene oxide and mixtures of these oxides. The polyalkylenepolyether polyols may be prepared from other starting materials such astetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures;epihalohydrins such as epichlorohydrin; as well as aralkylene oxidessuch as styrene oxide. The polyalkylene polyether polyols may haveeither primary or secondary hydroxyl groups.

Included among the polyether polyols are polyoxyethylene glycol,polyoxypropylene glycol,polyoxybutylene glycol, polytetramethyleneglycol, block copolymers, for example, combinations of polyoxypropyleneand polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethyleneglycols, poly-1,4-tetramethylene and polyoxyethylene glycols, andcopolymer glycols prepared from blends or sequential addition of two ormore alkylene oxides. The polyalkylene polyether polyols may be preparedby any known process such as, for example, the process disclosed byWurtz in 1859 and Encyclopedia of Chemical Technology, Vol. 7, pp.257-262, published by Interscience Publishers, Inc. (1951) or in U.S.Pat. No. 1,922,459.

Polyethers which are preferred include the alkylene oxide additionproducts of polyhydric alcohols such as ethylene glycol, propyleneglycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone,resorcinol glycerol, glycerine, 1,1,1-trimethylol-propane,1,1,1-trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, α-methylglucoside, sucrose, and sorbitol. Also included within the term"polyhydric alcohol" are compounds derived from phenol such as2,2-bis(4-hydroxyphenyl)-propane, commonly known as Bisphenol A.

Suitable organic amine starting materials include aliphatic andcycloaliphatic amines and mixtures thereof, having at least one primaryamino group, preferably two or more primary amino groups, and mostpreferable are the diamines. Specific non-limiting examples of aliphaticamines include monoamines having 1 to 12, preferably 1 to 6 carbonatoms, such as methylamine, ethylamine, butylamine, hexylamine,octylamine, decylamine and dodecylamine; aliphatic diamines such as1,2-diaminoethane, propylene diamine, 1,4-diaminobutane,1,6-diaminohexane, 2,2-dimethyl-,3-propanediamine,2-methyl-1,5-pentadiamine, 2,5-dimethyl-2,5-hexanediamine, and4-aminomethyloctane-1,8-diamine, and amino acid-based polyamines such aslysine methyl ester, lysine aminoethyl ester and cystine dimethyl ester;cycloaliphatic monoamines of 5 to 12, preferably of 5 to 8, carbon atomsin the cycloalkyl radical, such as cyclohexylamine and cyclo-octylamineand preferably cycloaliphatic diamines of 6 to 13 carbon atoms, such ascyclohexylenediamine, 4,4'-, 4,2'-, and 2,2'-diaminocyclohexylmethaneand mixtures thereof; aromatic monoamines of 6 to 18 carbon atoms, suchas aniline, benzylamine, toluidine and naphthylamine and preferablyaromatic diamines of 6 to 15 carbon atoms, such as phenylenediamine,naphthylenediamine, fluorenediamine, diphenyldiamine, anthracenediamine,and preferably 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'-, and2,2'-diaminodiphenylmethane, and aromatic polyamines such as2,4,6-triaminotoluene, mixtures of polyphenyl-polymethylene-polyamines,and mixtures of diaminidiphenylmethanes andpolyphenyl-polymethylene-polyamines. Preferred are ethylenediamine,propylenediamine, decanediamine, 4,4'-diaminophenylmethane,4,4'-diaminocyclohexylmethane, and toluenediamine.

Suitable initiator molecules also include alkanolamines such asethanolamine, diethanolamine, N-methyl- and N-ethylethanolamine,N-methyl- and N-ethyldiethanolamine and triethanolamine plus ammonia.

Suitable polyhydric polythioethers which may be condensed with alkyleneoxides include the condensation product of thiodiglycol or the reactionproduct of a dicarboxylic acid such as is disclosed above for thepreparation of the polyester polyols with any other suitable thioetherglycol.

The polyester polyol may also be a polyester amide such as is obtainedby including some amine or amino alcohol in the reactants for thepreparation of the polyesters. Thus, polyester amides may be obtained bycondensing an amino alcohol such as ethanolamine with the polycarboxylicacids set forth above or they may be made using the same components thatmake up the polyester polyol with only a portion of the components beinga diamine such as ethylene diamine.

Polyhydroxyl-containing phosphorus compounds which may be used includethose compounds disclosed in U.S. Pat. No. 3,639,542. Preferredpolyhydroxyl-containing phosphorus compounds are prepared from alkyleneoxides and acids of phosphorus having a P₂ O₅ equivalency of from about72 percent to about 95 percent.

Suitable polyacetals which may be condensed with alkylene oxides includethe reaction product of formaldehyde or other suitable aldehyde with adihydric alcohol or an alkylene oxide such as those disclosed above.

Suitable aliphatic thiols which may be condensed with alkylene oxidesinclude alkanethiols containing at least two --SH groups such as1,2-ethanedithiol, 1,2-propanedithiol, 1,2-propanedithiol, and1,6-hexanedithiol; alkene thiols such as 2-butene-1,4-dithiol; andalkyne thioIs such as 3-hexyne-1,6-dithiol.

Also suitable for mixture with the compound having polyester linkagesare polymer modified polyols, in particular, the so-called graftpolyols. Graft polyols are well known to the art and are prepared by thein situ polymerization of one or more vinyl monomers, preferablyacrylonitrile and styrene, in the presence of a polyether or polyesterpolyol, particularly polyols containing a minor amount of natural orinduced unsaturation. Methods of preparing such graft polyols may befound in columns 1-5 and in the Examples of U.S. Pat. No. 3,652,639; incolumns 1-6 and the Examples of U.S. Pat. No. 3,823,201; particularly incolumns 2-8 and the Examples of U.S. Pat. No. 4,690,956; and in U.S.Pat. No. 4,524,157; all of which patents are herein incorporated byreference.

Non-graft polymer modified polyols can also be mixed, for example, thoseprepared by the reaction of a polyisocyanate with an alkanolamine in thepresence of a polyol as taught by U.S. Pat. Nos. 4,293,470; 4,296,213;and 4,374,209; dispersions of polyisocyanurates containing pendant ureagroups as taught by U.S. Pat. No. 4,386,167; and polyisocyanuratedispersions also containing biuret linkages as taught by U.S. Pat. No.4,359,541. Other polymer modified polyols may be prepared by the in situsize reduction of polymers until the particle size is less than 20 μm,preferably less than 10 μm.

The aliphatic or cycloaliphatic C₄ -C₇ hydrocarbon has a boiling pointof 50° C. or less at 1 atmosphere, preferably 38° C. or less. Thehydrocarbon is physically active and has a sufficiently low boilingpoint to be gaseous at the exothermic temperatures caused by thereaction between the isocyanate and polyols, so as to foam the resultingpolyurethane matrix. The hydrocarbon blowing agents consist exclusivelyof carbon and oxygen, therefore, they are non-halogenated by definition.Examples of the C₄ -C₇ hydrocarbon blowing agents include linear orbranched alkanes, e.g. butane, isobutane, 2,3 dimethylbutane, n- andisopentane and technical-grade pentane mixtures, n- and isohexanes, andn- and isoheptanes. Since very good results are achieved with respect tothe stability of emulsions, the processing properties of the reactionmixture, and the lowering of the overall density in faced laminate boardwhen n-pentane, isopentane or n-hexane, or a mixture thereof is used,these alkanes are preferably employed, most preferably n-pentane andisopentane. Specific examples of alkenes are 1-pentene, 2-methylbutene,3-methylbutene, and 1-hexene, and of cycloalkanes are cyclobutane,preferably cyclopentane, cyclohexane or mixtures thereof.Preferentially, cyclopentane, n- and isopentane, and mixtures thereofare employed.

Other blowing agents which can be used in combination with the one ormore C₄ -C₇ hydrocarbon blowing agents may be divided into thechemically active blowing agents which chemically react with theisocyanate or with other formulation ingredients to release a gas forfoaming, and the physically active blowing agents which are gaseous atthe exotherm foaming temperatures or less without the necessity forchemically reacting with the foam ingredients to provide a blowing gas.Included with the meaning of physically active blowing agents are thosegases which are thermally unstable and decompose at elevatedtemperatures.

Examples of chemically active blowing agents are preferentially thosewhich react with the isocyanate to liberate gas, such as CO₂. Suitablechemically active blowing agents include, but are not limited to, water,mono- and polycarboxylic acids having a molecular weight of from 46 to300, salts of these acids, and tertiary alcohols.

Water is preferentially used as a co-blowing agent with the hydrocarbonblowing agent. Water reacts with the organic isocyanate to liberate CO₂gas which is the actual blowing agent. However, since water consumesisocyanate groups, an equivalent molar excess of isocyanate must be usedto make up for the consumed isocyanates.

The organic carboxylic acids used are advantageously aliphatic mon- andpolycarboxylic acids, e.g. dicarboxylic acids. However, other organicmono- and polycarboxylic acids are also suitable. The organic carboxylicacids may, if desired, also contain substituents which are inert underthe reaction conditions of the polyisocyanate polyaddition or arereactive with isocyanate, and/or may contain olefinically unsaturatedgroups. Specific examples of chemically inert substituents are halogenatoms, such as fluorine and/or chlorine, and alkyl, e.g. methyl orethyl. The substituted organic carboxylic acids expediently contain atleast one further group which is reactive toward isocyanates, e.g. amercapto group, a primary and/or secondary amino group, or preferably aprimary and/or secondary hydroxyl group.

Suitable carboxylic acids are thus substituted or unsubstitutedmonocarboxylic acids, e.g. formic acid, acetic acid, propionic acid,2-chloropropionic acid, 3-chloropropionic acid, 2,2-dichlorpropionicacid, hexanoic acid, 2-ethyl-hexanoic acid, cyclohexanecarboxylic acid,dodecanoic acid, palmitic acid, stearic acid, oleic acid,3-mercapto-propionic acid, glycoli acid, 3-hydroxypropionic acid, lacticacid, ricinoleic acid, 2-aminopropionic acid, benzoic acid,4-methylbenzoic acid, salicylic acid and anthranilic acid, andunsubstituted or substituted polycarboxylic acids, preferablydicarboxylic acids, e.g. oxalic acid, malonic acid, succinic acid,fumaric acid, maleic acid, glutaric acid, adipic acid, sebacic acid,dodecanedioic acid, tartaric acid, phthalic acid, isophthalic acid andcitric acid. Preferable acids are formic acid, propionic acid, aceticacid, and 2-ethylhexanoic acid, particularly formic acid.

The amine salts are usually formed using tertiary amines, e.g.triethylamine, dimethylbenzylamine, diethylbenzylamine,triethylenediamine, or hydrazine. Tertiary amine salts of formic acidmay be employed as chemically active blowing agents which will reactwith the organic isocyanate. The salts may be added as such or formed insitu by reaction between any tertiary amine (catalyst or polyol) andformic acid contained in the polyol composition.

Combinations of any of the aforementioned chemically active blowingagents may be employed, such as formic acid, salts of formic acid,and/or water.

Physically active blowing agents are those which boil at the exothermfoaming temperature or less, preferably at 50° C. or less at 1atmosphere. The most preferred physically active blowing agents arethose which have an ozone depletion potential of 0.05 or less. Examplesof other physically active blowing agents are dialkyl ethers,cycloalkylene ethers and ketones; hydrochlorofluorocarbons (HCFCs);hydrofluorocarbons (HFCs); perfluorinated hydrocarbons (HFCs);fluorinated ethers (HFCs); and decomposition products.

Any hydrochlorofluorocarbon blowing agent may be used in the presentinvention. Preferred hydrochlorofluorocarbon blowing agents include1-chloro-1,2-difluoroethane; 1-chloro-2,2-difluoroethane (142a);1-chloro-1,1-difluoroethane (142b); 1,1-dichloro-1-fluoroethanefluoroethane (141b); 1-chloro-1,1,2-trifluoroethane;1-chloro-1,2,2-trifluoroethane; 1,1-dichloro-1,2-difluoroethane;1-chloro-1,1,2,2-tetrafluoroethane (124a);1-chloro-1,2,2,2-tetrafluoroethane(124);1,1-dichloro-1,2,2-trifluoroethane;1,1-dichloro-2,2,2-trifluoroethane(123); and 1,2-dichloro-1,1,2-trifluoroethane (123a);monochlorodifluoromethane (HCFC-22); 1-chloro-2,2,2-trifluoroethane(HCFC-133a); gem-chlorofluoroethylene (R-1131a);chloroheptafluoropropane (HCFC-217); chlorodifluoroethylene (HCFC-1122);and transchlorofluoroethylene (HCFC-1131). The most preferredhydrochlorofluorocarbon blowing agent is 1,1-dichloro-1-fluoroethane(HCFC-141b).

Suitable hydrofluorocarbons, perfluorinated hydrocarbons, andfluorinated ethers include difluoromethane (HFC-32);1,1,1,2-tetrafluoroethane (HFC-134a); 1,1,2,2-tetrafluoroethane(HFC-134);1,1-difluoroethane (HFC-152a);1,2-difluoroethane (HFC-142),trifluoromethane;heptafluoropropane;1,1,1-trifluoroethane;1,1,2-trifluoroethane;1,1,1,2,2-pentafluoropropane;1,1,1,3-tetrafluoropropane; 1,1,2,3,3-pentafluoropropane;1,1,1,3,3-pentafluoro-n-butane; hexafluorocyclopropane (C-216);octafluorocyclobutane (C-318); perfluorotetrahydrofuran; perfluoroalkyltetrahydrofurans; perfluorofuran; perfluoro-propane,-butane,-cyclobutane,-pentane,-cyclopentane, and -hexane, -cyclohexane,-heptane, and -octane; perfluorodiethyl ether; perfluorodipropyl ether;and perfluoroethyl propyl ether.

Decomposition type physically active blowing agents which release a gasthrough thermal decomposition include pecan flour, amine/carbon dioxidecomplexes, and alkyl alkanoate compounds, especially methyl and ethylformates.

The total and relative amounts of blowing agents will depend upon thedesired foam density, the type of hydrocarbon, and the amount and typeof additional blowing agents employed. Polyurethane foam densitiestypical for rigid polyurethane insulation applications range from freerise densities of 1.3 to 2.5 pcf, preferably from 1.3 to 2.1 pcf, andoverall molded densities of 1.5 to 3.0 pcf. The amount by weight of allblowing agents is generally 10 php to 35 php, preferably 22 php to 28php (php means parts per hundred parts of all polyols). Based on theweight of all the foaming ingredients, the total amount of blowing agentis generally from 4 wt % to 15 wt %. The amount of hydrocarbon blowingagent, based on the weight of all the foaming ingredients, is also from4 wt. % to 15 wt %, preferably from 6 wt % to 8 wt %

Water is typically found in minor quantities in the polyols as abyproduct and may be sufficient to provide the desired blowing from achemically active substance. Preferably, however, water is additionallyintroduced into the polyol composition in amounts from 0.05 to 5 pbw,preferably from 0.25 to 1.0 php. The physically active blowing agents,if employed, make up the remainder of the blowing agent for a total offrom 10 php to 35 php, or 4 wt % to 15 wt. % based on the weight of allthe foaming ingredients.

The third c) compound is a polyoxyalkylene polyether monool initiatedwith a C₈ -C₂₄ fatty hydrocarbon having one alkylene oxide activehydrogen atom. The monool has a dual function, that of emulsifying thehydrocarbon in the polyol, the emulsion being stable for a period of atleast 30 minutes, and lowering the density of the resulting foam. By astable emulsion is meant that, for a period of at least 30 minutes,preferably for 2 hours, more preferably for 3 hours, the discretehydrocarbon phase does not settle out or rise to the top of thecontinuous polyol phase in the absence of agitation or mixing. Thehydrocarbon should remain uniformly dispersed throughout the continuouspolyol phase.

In one embodiment, one may mix the hydrocarbon blowing agent in a polyolpre-mix tank and have a stable emulsion without the need for constantagitation. Further, a separate hydrocarbon blowing agent feed line tothe mix head is no longer necessary. However, the scope of the inventionincludes a polyol composition of at least a polyol having polyesterlinkages, a C₄ -C₇ hydrocarbon blowing agent, and the monool. Thiscomposition may be formed, however momentarily, in the mix head byseparately metering each ingredients through its own feed line into themix head. If one desires to form an emulsion, the composition may beformed by first premixing the monool with the polyol and the blowingagent in a polyol pre-mix tank to form an emulsion, after which theemulsion is mixed with the isocyanate in the mix head. Alternatively,the monool and the polyol may be mixed together and fed through a lineto the mix head where the isocyanate and the blowing agent areseparately metered through their own individual lines.

Whatever method of adding the monool is used, the foam resulting fromthe polyol composition of the invention has a lowered density. The foammade with the polyol composition of the invention has a density which isat least 2.00% less than the density of a reference foam made at thesame isocyanate index and with all the same ingredients in the sameamounts except without said monool and adding an amount of a) polyolcorresponding to the amount of omitted monool, where the densities aremeasured from the core of free rise samples. Depending upon the amountof blowing agent used, the reduction in free rise foam density can bemore pronounced, such as 3.00 or 4.00% at 8-9 wt. % of blowing agentbased on the weight of all the foaming ingredients.

While one would normally expect to see a corresponding reduction in themechanical properties of a foam with reduced density, the foams madewith the polyol composition retain mechanical properties equivalent tothe foams made at higher densities, such as compressive strengths andinsulation values. In one embodiment of the invention, both GRF (glassreinforced facer) and aluminum faced foams made with the polyolcomposition have initial k-factors of 0.160 btu-in/hr-ft² -degrees F. orless, and 0.165 btu-in/hr-ft² -degrees F. or less at 100 days, whentested according to ASTM C518.

In another embodiment, the foams made with the polyol composition of theinvention not only have reduced densities and insulation values asstated above, but also are dimensionally stable. The foam has a volumechange, when aged from 1-28 days at 158 degrees F. and 100% r.h. of 3.0%or less, preferably of 2.0% or less; when aged from 1-28 days at 200degrees F. of 3.0% or less, preferably of 2.5% or less; and when agedfrom 1-7 days at -20 degrees F. of less than 2.0%, preferably of 1.5% orless, with none of the stated values exceeded at any point throughoutthe 28 days.

The polyoxyalkylene polyether monools used in the invention may beprepared by the simple addition of one or more alkylene oxides to aninitiator fatty hydrocarbon having one alkylene oxide active hydrogenrepresented by the general formula:

    R--X

where R represents a C₈ -C₂₄ branched or unbranched, saturated orethylenically unsaturated, aliphatic or alicyclic radical; preferably analiphatic linear, saturated or ethylenically unsaturated radical; morepreferably a linear alkyl (saturated) radical, and most preferably alinear C₁₂ -C₁₅ alkyl radical; and X represents OH, NRH, or SH,preferably OH.

In a preferred embodiment, the monool is initiated with a fatty alcohol,generically meaning that the R group is as stated above in its broadestsense, and the X group is OH. The fatty alcohol is preferably a branchedor unbranched C₈ -C₂₄ aliphatic primary or secondary alcohol, mostpreferably a branched or unbranched C₁₂ -C₁₅ alkyl primary alcohol. Asused herein, the designation of a fatty alcohol or a C₁₂ -C₁₅ fattyalcohol, or any such similar designation includes those instances wherethe initiator may be composed purely of molecules each having the samenumber of carbon atoms and the same structure, the same number of carbonatoms but structural isomers or stereoisomers of each other, or amixture of linear compounds having different numbers of carbon atoms solong as at least 90 wt. % of the molecules in the mixture have carbonchain lengths within the range described above. Thus, an initiatorcomprised of C₁₂ -C₁₅ fatty alcohols, if a mixture of differing carbonchain lengths is used, means that at least 90 wt. % of the alcoholmolecules have 12 to 15 carbon atoms. There is no limitation on themolecular weight distribution within the described range of carbon atomnumbers. Mixtures of fatty alcohols having different numbers of carbonatoms are preferred. Alternatively, one may also employ a monodisperseinitiator within the described range of carbon atoms.

It is preferred to use primary fatty hydrocarbons which have a linearstructure. While some degree of branching may be tolerated, thehydrophobic properties of the monool diminish as the degree of branchingincreases. If a branched fatty hydrocarbon is used, it is preferred thatthe branched group be an alkyl group of 3 or less carbon atoms inlength, more preferred located two or three carbons away from thepolyoxyalkylene chain. Likewise, the hydrophobicity of the fatty chainis most enhanced when the alcohol functionality is terminal on thechain, which is always the case with primary fatty alcohols.

Examples of the preferred fatty alcohols include octyl alcohol, nonylalcohol, decyl alcohol, dodecyl alcohol, tetradecyl alcohol, cetylalcohol, lauryl alcohol, palmityl alcohol, stearyl alcohol, hydrogenatedtallow alcohol, and mixtures thereof.

The monool of the invention is prepared by adding one or more types ofalkylene oxides onto the initiator molecule. Examples of alkylene oxidesare 1,3-propylene oxide, 1,2- and 2,3-butylene oxide, amylene oxides,and preferably ethylene oxide and 1,2-propylene oxide and mixtures ofthese oxides. The monools may be prepared from other starting materialssuch as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures;epihalohydrins such as epichlorohydrin; as well as aralkylene oxidessuch as styrene oxide.

The alkylene oxides added to the initiator may be pure or a mixture oftwo or more alkylene oxides, preferably a mixture. In a preferredembodiment, a mixture of ethylene oxide and 1,2 propylene oxide is addedonto the initiator molecule. The oxide mixture may be added in severalsteps or in one continuous step. A mixture of alkylene oxides such asethylene oxide and propylene oxide added in one continuous step to theinitiator will produce a random distribution of oxyethylene andoxypropylene units along the polyoxyalkylene chain, known as a hetericpolyoxyethylene-polyoxypropylene polyether monool. Alternatively, thealkylene oxides may be added in a step wise fashion to the initiator toproduce block(s) of oxyethylene units and block(s) of oxypropylene unitsin any order desired and with as many blocks as desired. In thisalternative, a preferable embodiment is to make a 2 block monool havingan internal block of oxyethylene units and a terminal block ofoxypropylene units. A further alternative is to add onto the initiator ablock of one alkylene oxide and in a second step add a mixture ofalkylene oxides onto the block to make a block-heteric polyether monool.

The amount of alkylene oxide added will vary depending on the typealkylene oxides added. In one preferred embodiment, the amount ofalkylene oxides added is sufficient to make a monool having a numberaverage molecular weight of 1000 or less, more preferably, 800 or less,not counting the weight of the initiator molecule. In general, the totalnumber of moles of alkylene oxides added onto the initiator molecule isfrom 2-20 moles, more preferably from 6-15 moles. It is preferred thatthe alkylene oxides added are ethylene oxide and 1,2 propylene oxide.The molar ratio of ethylene oxide to 1,2 propylene oxide in thispreferred embodiment is from 1:3 to 1:0.20, more preferably from 1:1.75to 1:0.45. The average number of moles of ethylene oxide in thispreferred embodiment ranges from 3 to 11, more preferably from 4.0 to9.0, while the average number of moles of 1,2-propylene oxide rangesfrom 2.2 to 10.0, more preferably from 2.5 to 8.5. The method ofaddition may be continuous or step-wise in this embodiment.

The addition of alkylene oxides to make the monools are generallycarried out in the presence of an alkaline catalyst. Examples includesodium hydroxide, potassium hydroxide, sodium ethylate, sodiummethylate, potassium acetate, sodium acetate, and trimethylamine. Thereaction is usually carried out at elevated temperatures and pressures.The catalyst may be neutralized with a carboxylic acid.

The amount of monool used in the polyol composition is an amounteffective to emulsify the blowing agent in the polyols for a period ofat least thirty minutes. If one chooses, however, to add the C₄ -C₇hydrocarbon blowing agent at the mix head rather than forming anemulsion, the amount of monool added to the polyol is any amount desiredto produce a foam having a reduced density. Usual amounts of monoolrange from 6 php-12 php.

Examples of monools include, but are not limited to, the Plurafac®surfactants sold by BASF Corporation. Plurafac RA-40 monool is a C₁₃-C₁₅ fatty alcohol onto which is added about 7 moles of propylene oxideand about 4 moles of ethylene oxide. Plurafac D-25 monool is a C₁₃ -C₁₅fatty alcohol onto which is added about 5 moles of propylene oxide andabout 10 moles of ethylene oxide. Plurafac RA-50 monool is a mixture ofequal parts of Plurafac D-25 and Plurafac RA40. Other useful Plurafacmonools are RA-20, RA-30, RA43, RA-50, B25-5, B-26, and C-17. Similar toPlurafac RA30 and RA40 are Polytergent S305LF and S405LF manufactured byOlin Chemical. Examples of ethoxylated fatty alcohols include thosemanufactured by Shell Chemical Company under the name of Dobanol® 25-7,Dobanol 23-6.5, and Dobanol 45-11 (containing about 7 moles of ethyleneoxide onto a C₁₂ -C₁₅ fatty alcohol, about 6.5 moles of ethylene oxideonto a C₁₂ -C₁₃ fatty alcohol, and about 11 moles of ethylene oxideadded onto a C₁₄ -C₁₅ fatty alcohol, respectively). Examples of linearsecondary fatty alcohols onto which are added alkylene oxides are thosemanufactured by Union Carbide Corp. under the name of Tergitol 15-S-7and Tergitol 15-S-9 (containing about 7 moles of ethylene oxide addedonto a mixture of C₁₁ -C₁₅ secondary fatty alcohol and about 9 moles ofethylene oxide added onto the same secondary fatty alcohols,respectively).

Additional optional ingredients in the polyol composition may includeisocyanate and/or isocyanurate promoting catalysts, surfactants, flameretardants, and fillers.

Catalysts may be employed which greatly accelerate the reaction of thecompounds containing hydroxyl groups and with the modified or unmodifiedpolyisocyanates. Examples of suitable compounds are cure catalysts whichalso function to shorten tack time, promote green strength, and preventfoam shrinkage. Suitable cure catalysts are organometallic catalysts,preferably organotin catalysts, although it is possible to employ metalssuch as lead, titanium, copper, mercury, cobalt, nickel, iron, vanadium,antimony, and manganese. Suitable organometallic catalysts, exemplifiedhere by tin as the metal, are represented by the formula: R_(n) Sn₂,wherein R is a C₁ -C₈ alkyl or aryl group, R¹ is a C₀ -C₁₈ methylenegroup optionally substituted or branched with a C₁ -C₄ alkyl group, Y ishydrogen or an hydroxyl group, preferably hydrogen, X is methylene, an--S--, an --SR² COO--, --SOOC--, an --O₃ S--, or an --OOC-- groupwherein R² is a C₁ -C₄ alkyl, n is 0 or 2, provided that R¹ is C₀ onlywhen X is a methylene group. Specific examples are tin (II) acetate, tin(II) octanoate, tin (II) ethylhexanoate and tin (II) laurate; anddialkyl (1-8C) tin (IV) salts of organic carboxylic acids having 1-32carbon atoms, preferably 1-20 carbon atoms, e.g., diethyltin diacetate,dibutyltin diacetate, dibutyltin diacetate, dibutyltin dilaurate,dibutyltin maleate, dihexyltin diacetate, and dioctyltin diacetate.Other suitable organotin catalysts are organotin alkoxides and mono orpolyalkyl (1-8C) tin (IV) salts of inorganic compounds such as butyltintrichloride, dimethyl- and diethyl- and dibutyl- and dioctyl- anddiphenyl- tin oxide, dibutyltin dibutoxide, di(2-ethylhexyl) tin oxide,dibutyltin dichloride, and dioctyltin dioxide. Preferred, however, aretin catalysts with tin-sulfur bonds which are resistant to hydrolysis,such as dialkyl (1-20C) tin dimercaptides, including dimethyl-,dibutyl-, and dioctyl- tin dimercaptides.

Tertiary amines also promote urethane linkage formation, and includetriethylamine, 3-methoxypropyldimethylamine, triethylenediamine,tributylamine, dimethylbenzylamine, N-methyl-, N-ethyl- andN-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine,N,N,N',N'-tetramethylbutanediamine or -hexanediamine, N,N,N'-trimethylisopropyl propylenediamine, pentamethyldiethylenetriamine,tetramethyldiaminoethyl ether, bis(dimethylaminopropyl)urea,dimethylpiperazine, 1-methyl-4-dimethylaminoethylpiperazine,1,2-dimethylimidazole, 1-azabicylooctane and preferably1,4-diazabicylooctane, and alkanolamine compounds, such astriethanolamine, triisopropanolamine, N-methyl- andN-ethyldiethanolamine and dimethylethanolamine.

To prepare the polyisocyanurate (PIR) and the PUR-PIR foams of theinvention, a polyisocyanurate catalyst is employed. Suitablepolyisocyanurate catalysts are alkali salts, for example, sodium salts,preferably potassium salts and ammonium salts, of organic carboxylicacids, expediently having from 1 to 8 carbon atoms, preferably 1 or 2carbon atoms, for example, the salts of formic acid, acetic acid,propionic acid, or octanoic acid, and tris(dialkylaminoethyl)-,tris(dimethylamninopropyl)-, tris(dimethylaminobutyl)- and thecorresponding tris(diethylaminoalkyl)-s-hexahydrotriazines. However,(trimethyl-2-hydroxypropyl)ammonium formate,(trimethyl-2-hydroxypropyl)ammonium octanoate, potassium acetate,potassium formate and tris(dimethylamninopropyl)-s-hexahydrotriazine arepolyisocyanurate catalysts which are generally used. The suitablepolyisocyanurate catalyst is usually used in an amount of from 1 to 10parts by weight, preferably from 1.5 to 8 parts by weight, based on 100parts by weight of the total amount of polyols.

Examples of suitable flame retardants are tetrakis(2-chloroethyl)ethylene phosphonate, tris(1,3-dichloropropyl) phosphate,tris(beta-chloroethyl) phosphate, tricresyl phosphate,tris(2,3-dibromopropyl)phosphate,tris(beta-chloropropyl)phosphate,tricresyl phosphate, andtris(2,3-dibromopropyl) phosphate.

In addition to the above-mentioned halogen-substituted phosphates, it isalso possible to use inorganic or organic flameproofing agents, such asred phosphorus, aluminum oxide hydrate, antimony trioxide, arsenicoxide, ammonium polyphosphate (Exolit®) and calcium sulfate, expandablegraphite or cyanuric acid derivatives, e.g., melamine, or mixtures oftwo or more flameproofing agents, e.g., ammonium polyphosphates andmelamine, and, if desired, corn starch, or ammonium polyphosphate,melamine, and expandable graphite and/or, if desired, aromaticpolyesters, in order to flameproof the polyisocyanate polyadditionproducts. In general, from 2 to 50 parts by weight, preferably from 5 to25 parts by weight, of said flameproofing agents may be used per 100parts by weight of the polyols.

Optional fillers are conventional organic and inorganic fillers andreinforcing agents. Specific examples are inorganic fillers, such assilicate minerals, for example, phyllosilicates such as antigorite,serpentine, hornblendes, amphiboles, chrysotile, and talc; metal oxides,such as kaolin, aluminum oxides, titanium oxides and iron oxides; metalsalts, such as chalk, baryte and inorganic pigments, such as cadmiumsulfide, zinc sulfide and glass, inter alia; kaolin (china clay),aluminum silicate and coprecipitates of barium sulfate and aluminumsilicate, and natural and synthetic fibrous minerals, such aswollastonite, metal, and glass fibers of various lengths. Examples ofsuitable organic fillers are carbon black melamine, colophony,cyclopentadienyl resins, cellulose fibers, polyamide fibers,polyacrylonitrile fibers, polyurethane fibers, and polyester fibersbased on aromatic and/or aliphatic dicarboxylic acid esters, and inparticular, carbon fibers.

The inorganic and organic fillers may be used individually or asmixtures and may be introduced into the polyol composition or isocyanateside in amounts of from 0.5 to 40 percent by weight, based on the weightof components (the polyols and the isocyanate); but the content of mats,nonwovens and wovens made from natural and synthetic fibers may reachvalues of up to 80 percent by weight.

The organic polyisocyanates include all essentially known aliphatic,cycloaliphatic, araliphatic and preferably aromatic multivalentisocyanates. Specific examples include: alkylene diisocyanates with 4 to12 carbons in the alkylene radical such as 1,12-dodecane diisocyanate,2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentamethylenediisocyanate, 1,4-tetramethylene diisocyanate and preferably1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as1,3- and 1,4-cyclohexane diisocyanate as well as any mixtures of theseisomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane(isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene diisocyanate aswell as the corresponding isomeric mixtures, 4,4'- 2,2'-, and2,4'-dicyclohexylmethane diisocyanate as well as the correspondingisomeric mixtures and preferably aromatic diisocyanates andpolyisocyanates such as 2,4- and 2,6-toluene diisocyanate and thecorresponding isomeric mixtures 4,4'-, 2,4'-, and 2,2'-diphenylmethanediisocyanate and the corresponding isomeric mixtures, mixtures of 4,4'-and 2,4'-diphenylmethane diisocyanates and polyphenylenepolymethylenepolyisocyanates (polymeric MDI), as well as mixtures of polymeric MDIand toluene diisocyanates. The organic di- and polyisocyanates can beused individually or in the form of mixtures.

Frequently, so-called modified multivalent isocyanates, i.e., productsobtained by the partial chemical reaction of organic diisocyanatesand/or polyisocyanates are used. Examples include diisocyanates and/orpolyisocyanates containing ester groups, urea groups, biuret groups,allophanate groups, carbodiimide groups, isocyanurate groups, and/orurethane groups. Specific examples include organic, preferably aromatic,polyisocyanates containing urethane groups and having an NCO content of33.6 to 15 weight percent, preferably 31 to 21 weight percent, based onthe total weight, e.g., with low molecular weight diols, triols,dialkylene glycols, trialkylene glycols, or polyoxyalkylene glycols witha molecular weight of up to 1500; modified 4,4'-diphenylmethanediisocyanate or 2,4- and 2,6-toluene diisocyanate, where examples of di-and polyoxyalkylene glycols that may be used individually or as mixturesinclude diethylene glycol, dipropylene glycol, polyoxyethylene glycol,polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropyleneglycol, and polyoxypropylene polyoxyethylene glycols or-triols.Prepolymers containing NCO groups with an NCO content of 25 to 9 weightpercent, preferably 21 to 14 weight percent, based on the total weightand produced from the polyester polyols and/or preferably polyetherpolyols described below; 4,4'-diphenylmethane diisocyanate, mixtures of2,4'- and 4,4'-diphenylmethane diisocyanate, 2,4,- and/or 2,6-toluenediisocyanates or polymeric MDI are also suitable. Furthermore, liquidpolyisocyanates containing carbodiimide groups having an NCO content of33.6 to 15 weight percent, preferably 31 to 21 weight percent, based onthe total weight, have also proven suitable, e.g., based on 4,4'- and2,4'- and/or 2,2'-diphenylmethane diisocyanate and/or 2,4'- and/or2,6-toluene diisocyanate. The modified polyisocyanates may optionally bemixed together or mixed with unmodified organic polyisocyanates such as2,4'- and 4,4'-diphenylmethane diisocyanate, polymeric MDI, 2,4'- and/or2,6-toluene diisocyanate.

Preferably, the isocyanate used to make the closed cell rigid foams ofthe invention contain polymeric MDI, with the average functionality ofthe isocyanate component used to react with the polyol composition being2.2 or more, more preferably 2.5 or more, most preferably 2.7 or more.

The foams of the invention are closed celled, meaning that greater than80% of the cells are closed as measured for uncorrected porosity.Preferably, greater than 85%, more preferably 90% or more of the cellsare closed as measured for uncorrected porosity. The foams of theinvention are also rigid, meaning that they have a compressive strengthto tensile strength ratio of at least 1.0 and an elongation at yield ofless than 10%.

Polyol A is a polyester polyol having an OH number of about 240, and afunctionality between 2-2.2, commercially available from Stepan Company.

Pluronic® L-44 is a polyoxyethylene-polyoxypropylene adduct havingoxyethylene termination and an OH number of about 51, commerciallyavailable from BASF Corporation.

Pluronic® L-64 is a polyoxyethylene-polyoxypropylene adduct havingoxyethylene termination and an OH number of about 38.7, commerciallyavailable from BASF Corporation.

Pluronic® 25R4 is a polyoxyethylene-polyoxypropylene adduct havingoxypropylene termination and an OH number of about 31.2, commerciallyavailable from BASF Corporation.

Plurafac® RA20 is a polyoxyethylene-polyoxypropylene block monool of C₁₂-C₁₅ fatty monohydroxyl alcohols, terminated with oxypropylene units,having an OH number of about 71, commercially available from BASFCorporation. About 8 moles of ethylene oxide and about 4 moles ofpropylene oxide were added onto the initiator.

Plurafac® RA30 is a polyoxyethylene-polyoxypropylene block monool of C₁₂-C₁₅ fatty monohydroxyl alcohols, terminated with oxypropylene units,having an OH number of about 90, commercially available from BASFCorporation. About 6 moles of ethylene oxide and about 3 moles ofpropylene oxide were added onto the initiator.

Plurafac® RA40 is a polyoxyethylene-polyoxypropylene heteric monool ofC₁₂ -C₁₅ fatty monohydroxyl alcohols, having an OH number of about 69,commercially available from BASF Corporation. About 5 moles of ethyleneoxide and about 7 moles of propylene oxide were added onto theinitiator.

DBE is a dibasic ester.

B-8462 is a surfactant, commercially available from Goldschmidt.

K Hexcem 977 is potassium octoate, a trimerization catalyst,commercially available from Mooney Chem.

Polycat 5 is an amine catalyst, commercially available from AirProducts.

N-pentane is 99.6% pure pentane commercially available from PhillipsPetro.

Cyclopentane is 70% commercial grade cyclopentane, the remainder beingmixtures of other hydrocarbons such as pentane and its isomer(s),commercially available from Phillips Petro.

Iso A is a polymeric MDI having a free NCO content of 31, a viscosity ofabout 700 cps at 25° C., and having a functionality of greater than 2.7,commercially available from BASF Corporation.

EXAMPLE 1

The ingredients listed in Table 1, except for the isocyanate, were mixedtogether in a stainless steel 3 gallon pre-mix tank in the amountsstated. A pneumatic mixer equipped with a German mix blade was used toblend the ingredients at about 1200 rpm for about 30 minutes. Thepre-mix tank was positioned on a load scale to measure the weight of theingredients during the blending operation, and any hydrocarbon gasescaping was continually replenished during the blending to keep theparts by weight of the gas constant. I noticed that the blended polyolcomposition for samples 6 and 7 below formed a stable emulsion, meaningthat no phase separation between the pentane blowing agent and thepolyols was apparent after letting the polyol composition sit for atleast 30 minutes. Even after letting the polyol composition sit stillfor 3 hours without agitation, I could detect no phase separation.Subsequently, the pre-mix tank was attached to a resin day tank on anEdge Sweet II impingement mix machine. The contents of the pre-mix tankwere gravity fed to the resin day tank and kept under agitation. When ashot of material was required, the polyol composition in the day tankwas pumped through an in-line mixer to the mix head, where it wasimpingement mixed with the Iso A fed from a separate line. The resin daytank and the iso tank were kept at about 23° C. The mix head pressurewas about 2000 psi, and the throughput was about 100 g/s. Theimpingement mixed polyol composition and isocyanate were shot into4"×10"×10" wooden boxes fitted with cake boxes of the same dimension.The resulting foam inside the cake boxes were allowed to cure, afterwhich the foams were tested for their mechanical properties reportedbelow in Table 2.

For the foams made with facers, separate batches were blended using thesame ingredients and amounts reported in Table 1 below by the sameprocedure noted above. The foams were shot from the Edge Sweet IImachine into 2"×12"×12" aluminum molds preheated to 130° F. and faced oneach half with either aluminum or glass reinforced facer (GRF). Thefoams were allowed to rise, cure, and were then demolded after about 5minutes. The aluminum facer was about 1 mil thick.

Cup densities reported in Table 2 are free rise foams shot from the EdgeSweet II machine into #10 lily cups. The core densities were measuredfrom a core taken from the cake box foams.

                                      TABLE 1                                     __________________________________________________________________________    Sample  1   2   3   4   5   6   7   8                                         __________________________________________________________________________    Polyol A                                                                              100.0                                                                             100.0                                                                             100.0                                                                             90.0                                                                              90.0                                                                              90.0                                                                              90.0                                                                              100.0                                     Pluronic L-44                                                                         9.00                                                                              9.00                                                                              9.00                                                                              --  --  --  --  --                                        Pluronic 25R4                                                                         --  --  --  10.00                                                                             --  --  --  --                                        Pluronic L-64                                                                         --  --  --  --  10.00                                                                             --  --  --                                        Plurafac RA-20                                                                        --  --  --  --  --  10.00                                                                             --  --                                        Plurafac RA-40                                                                        --  --  --  --  --  --  10.00                                                                             --                                        DBE     --  1.00                                                                              3.00                                                                              --  --  --  --  --                                        B-8462  3.00                                                                              3.00                                                                              3.00                                                                              4.00                                                                              4.00                                                                              4.00                                                                              4.00                                                                              3.00                                      K Hexcem 977                                                                          5.00                                                                              5.00                                                                              5.00                                                                              5.00                                                                              5.00                                                                              5.00                                                                              5.00                                                                              5.00                                      Polycat 5                                                                             0.20                                                                              0.20                                                                              0.20                                                                              0.20                                                                              0.20                                                                              0.20                                                                              0.20                                                                              0.20                                      Water   0.50                                                                              0.50                                                                              0.50                                                                              0.50                                                                              0.50                                                                              0.50                                                                              0.50                                                                              0.50                                      n-Pentane                                                                             27.00                                                                             27.00                                                                             27.00                                                                             27.00                                                                             27.00                                                                             20.00                                                                             20.00                                                                             --                                        Cyclopentane                                                                          --  --  --  --  --  --  --  27.00                                     Resin Total                                                                           144.70                                                                            145.70                                                                            147.70                                                                            136.70                                                                            136.70                                                                            129.70                                                                            129.70                                                                            135.70                                    __________________________________________________________________________    Iso A   199.8                                                                             199.8                                                                             199.8                                                                             181.4                                                                             181.9                                                                             184.3                                                                             184.0                                                                             196.5                                     Index   300 300 300 300 300 300 300 300                                       Overall Total                                                                         344.50                                                                            345.50                                                                            347.50                                                                            318.10                                                                            318.60                                                                            314.00                                                                            313.70                                                                            332.20                                    % B.A. based                                                                          7.8 7.8 7.8 8.5 8.5 6.4 6.4 8.1                                       on overall                                                                    total                                                                         __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Sample 1    2   3   4   5    6   7   8                                        __________________________________________________________________________    Cup Density                                                                          1.84 1.64                                                                              1.58                                                                              1.50                                                                              1.48 1.83                                                                              1.90                                                                              1.64                                     (pcf)                                                                         Core Density                                                                         2.30 2.38                                                                              1.78                                                                              1.66                                                                              1.64 2.01                                                                              2.10                                                                              1.83                                     (pcf)                                                                         k-factor.sup.1                                                                       0.162                                                                              0.157                                                                             0.160                                                                             0.154                                                                             0.161                                                                              0.145                                                                             0.148                                                                             0.142                                    initial                                                                       k-factor 10                                                                          0.172                                                                              0.184                                                                             0.174                                                                             0.170                                                                             0.173                                                                              0.153                                                                             0.153                                                                             0.161                                    days                                                                          k-factor 30                                                                          0.183                                                                              0.199                                                                             0.188                                                                             0.180                                                                             0.184                                                                              0.160                                                                             0.162                                                                             0.173                                    days                                                                          k-factor 100                                                                         --   --  --  --  --   --  --  --                                       days                                                                          k-factor                                                                             0.165                                                                              0.158                                                                             0.152                                                                             0.168                                                                             0.160                                                                              0.155                                                                             0.147                                                                             0.157                                    initial                                                                       aluminum                                                                      GRF    0.152                                                                              0.152                                                                             0.149                                                                             0.158                                                                             0.152                                                                              0.145                                                                             0.142                                                                             0.146                                    k-factor 10                                                                          0.160                                                                              0.156                                                                             0.154                                                                             0.175                                                                             0.162                                                                              0.155                                                                             0.147                                                                             0.156                                    days                                                                          aluminum                                                                      GRF    0.152                                                                              0.163                                                                             0.160                                                                             0.161                                                                             0.157                                                                              0.151                                                                             0.147                                                                             0.147                                    k-factor 30                                                                          0.162                                                                              0.170                                                                             0.159                                                                             0.177                                                                             0.166                                                                              0.160                                                                             0.154                                                                             0.172                                    days                                                                          aluminum                                                                      GRF    0.158                                                                              0.162                                                                             0.157                                                                             0.178                                                                             0.161                                                                              0.154                                                                             0.163                                                                             0.159                                    k-factor 100                                                                         0.166                                                                              0.175                                                                             0.163                                                                             0.182                                                                             0.172                                                                              0.160                                                                             0.157                                                                             0.168                                    days                                                                          aluminum                                                                      GRF    0.161                                                                              0.166                                                                             0.175                                                                             0.177                                                                             0.168                                                                              0.159                                                                             0.155                                                                             0.148                                    % closed cell                                                                        88.83                                                                              86.49                                                                             95.78                                                                             94.57                                                                             92.69                                                                              92.62                                                                             98.16                                                                             96.01                                    uncorrected                                                                   % closed cell                                                                        96.06                                                                              95.01                                                                             99.95                                                                             99.97                                                                             99.83                                                                              99.95                                                                             99.97                                                                             99.96                                    corrected                                                                     Parallel 10%                                                                         32.0 35.8                                                                              31.2                                                                              26.4                                                                              23.7 32.9                                                                              34.4                                                                              34.7                                     comp.                                                                         Parallel                                                                             9.4  N.D.                                                                              N.D.                                                                              N.D.                                                                              6.1  5.6 6.7 7.8                                      comp. yield                                                                   deflection %                                                                  Perpend. 10%                                                                         9.2  8.8 18.1                                                                              21.6                                                                              7.9  18.0                                                                              15.2                                                                              12.4                                     comp.                                                                         Perpend.                                                                             N.D. N.D.                                                                              N.D.                                                                              N.D.                                                                              N.D. N.D.                                                                              N.D.                                                                              N.D.                                     comp. yield                                                                   deflection %                                                                  Butler Chimn                                                                         26.27                                                                              33.18                                                                             42.34                                                                             31.96                                                                             36.14                                                                              44.96                                                                             47.45                                                                             48.82                                    wt.    29.47                                                                              37.24                                                                             43.50                                                                             30.88                                                                             33.16                                                                              41.22                                                                             40.59                                                                             47.64                                    retention %                                                                          25.91            30.30                                                                              42.69                                                                             43.98                                                                             39.50                                    158 F. @                                                                      100% R.H.                                                                     1 day  5.7  -3.0                                                                              0.3 0.8 4.9  -0.1                                                                              0.4 1.4                                      2 days 7.2  1.4 0.9 3.0 5.4  0.3 1.0 1.3                                      7 days 8.7  8.5 1.0 2.0 8.0  0.4 1.0 2.2                                      14 days                                                                              10.0 8.3 0.9 1.9 9.8  0.9 1.7 3.1                                      28 days                                                                              10.4 0.7 0.8 1.2 11.0 1.0 1.8 2.5                                      200 F.                                                                        1 day  21.1 5.4 3.7 6.9 1.0  0.4 0.5 1.3                                      2 days 20.8 5.3 7.1 7.7 1.8  0.4 0.8 1.7                                      7 days 14.8 2.1 8.1 7.5 6.5  1.6 1.3 2.6                                      14 days                                                                              11.6 1.4 4.3 3.9 12.6 1.4 1.1 2.4                                      28 days                                                                              9.8  24  3.2 2.7 10.3 2.1 1.4 4.0                                      -20 F.                                                                        1 day  -35.7                                                                              -4.7                                                                              0.5 0.6 -6.2 1.2 0.9 -8.0                                     2 days -34.2                                                                              -5.8                                                                              0.1 0.3 -7.0 0.6 0.6 -10.8                                    7 days -31.9                                                                              -1.1                                                                              0.3 0.4 -11.0                                                                              0.0 0.7 -12.3                                    __________________________________________________________________________     .sup.1 All the reported kfactors are in btuin/hr-ft.sup.2degrees F.      

The k factors of the cake box foams were improved when the polyolcomposition contained the Plurafac® monools. Comparing samples 6 and 7with samples 1-5 and 8, it is evident that the monools had a positiveinfluence on the insulation factors of the rigid foams. The aluminum andGRF faced foams made with the monools (samples 6 and 7) also showed animprovement in k-factors over foams made with the dihydroxyl compoundsof samples 1-5, although the difference was not as dramatic as notedwith the unfaced rigid foam samples. The compressive strengths at 10%deflection and the percentage deflection at yield in samples 6 and 7were as good as or better than the remaining samples made withdihydroxyl compounds or without an additive. The flammability propertiesof the foams made with the monools was better than foams made with thedihydroxyl compounds and as good as the cyclopentane blown foam madewithout an additive, as demonstrated by the higher Butler Chimney weightretentions. The flammability characteristics of the foam samples wouldbe improved in all samples, however, if a flame retardant were added tothe formulation.

EXAMPLE 2

In this example, the effect of the monools upon foam density was tested.Four categories of foams were tested: those made with the monool, withcyclopentane or n-pentane as blowing agents, and those made without themonool, blown with cyclopentane or n-pentane. Master batches A (withoutthe monool) and B (with the monool) were first prepared in individualstainless steel pre-mix tanks according to the procedure described inExample 1. The blowing agents were added in the amounts stated in Table3 below to make a polyol composition, which was subsequently attached tothe Edge Sweet II machine for reaction with the Iso A in the mix headand foaming in the cake box, all according to the procedure ofExample 1. The density of each foam sample was tested for overalldensity and a core sample measuring 3"×3"×3", taken from eachcorresponding foam. The results are reported in Table 3.

Master batch blend A was made of 1200 g of Polyol A, 48 g of B-8462, 48g of Hexchem 977, 1.8 g of Polycat 5, 180 g of Fyrol PCF fire retardant,and 6.0 g of distilled water, for a total of 1483.8 grams. Master batchblend B was the same as blend A, except that 120 g of Plurafac® RA40monool partially replaced Polyol A, leaving 1080 g of Polyol A. Allother ingredients were in the same amount and type.

                  TABLE 3                                                         ______________________________________                                        Sample   1       2       3     4     5     6                                  ______________________________________                                        Blend A  125.65  --      123.65                                                                              --    123.65                                                                              --                                 Blend B  --      123.65  --    123.65                                                                              --    123.65                             n-pentane                                                                              20.50   19.64   24.20 23.20 27.90 26.80                              cyclopentane                                                                           --      --      --    --    --    --                                 total resin                                                                            144.15  143.29  147.85                                                                              146.85                                                                              151.55                                                                              150.45                             Iso A    197.0   184.0   197.0 184.0 197.0 184.0                              total                                                                         overall                                                                       Index    300     300     300   300   300   300                                % Blowing                                                                              6       6       7     7     8     8                                  Agent                                                                         Overall  2.03    1.96    1.87  1.79  1.72  1.62                               Density                                                                       (pcf)                                                                         Core     1.91    1.84    1.69  1.65  1.55  1.47                               Density                                                                       (pcf)                                                                         ______________________________________                                        Sample   7       8       9     10    11    12                                 ______________________________________                                        Blend A  123.65  --      123.65                                                                              --    123.65                                                                              --                                 Blend B  --      123.65  --    123.65                                                                              --    123.65                             n-pentane                                                                              31.80   30.43   --    --    --    --                                 cyclopentane                                                                           --      --      20.50 19.64 24.20 23.20                              total resin                                                                            155.45  154.08  144.15                                                                              143.29                                                                              147.85                                                                              146.85                             Iso A    197.0   184.0   197.0 184.0 197.0 184.0                              total                                                                         overall                                                                       Index    300     300     300   300   300   300                                % Blowing                                                                              9       9       6     6     7     7                                  Agent                                                                         Overall  1.58    1.56    2.37  2.41  2.04  2.04                               Density                                                                       (pcf)                                                                         Core     1.42    1.37    2.10  2.11  1.81  1.77                               Density                                                                       (pcf)                                                                         ______________________________________                                        Sample   13        14        15      16                                       ______________________________________                                        Blend A  123.65    --        12.65   --                                       Blend B  --        123.65    --      123.65                                   n-pentane                                                                              --        --        --      --                                       cyclopentane                                                                           27.90     26.80     31.8    30.4                                     total resin                                                                            151.55    150.45    155.48  154.0                                    Iso A    197.0     184.0     197.0   184.0                                    total                                                                         overall                                                                       Index    300       300       300     300                                      % Blowing                                                                              8         8         9       9                                        Agent                                                                         Overall  1.88      1.87      1.71    1.72                                     Density                                                                       (pcf)                                                                         Core     1.62      1.59      1.47    1.44                                     Density                                                                       (pcf)                                                                         ______________________________________                                    

Foam samples 1-8 were blown with n-pentane, while foam samples 9-16 wereblown with cyclopentane. The density of each foam at a given percentageof blowing agent was measured with and without the monool Plurafac®RA40. In samples 1-8, it is evident that the foams made with the batch Bcontaining the monool were lower in density than the foams made withoutthe monool using the same percentage and type of blowing agent, andusing the same amount and type of ingredients in the batch except forthe monool. Using cyclopentane as the blowing agent, the reduction indensity was apparent in the core density at blowing agent levels above6%. The reduction in the overall density, however, was not noticeable.

What we claim is:
 1. A polyol composition comprising:a) a polyol havingpolyester linkages; b) an aliphatic or cycloaliphatic C₄ -C₇hydrocarbon; c) a polyoxyalkylene polyether monool initiated with a C₈-C₂₄ fatty hydrocarbon having one alkylene oxide active hydrogen atom.2. The polyol composition of claim 1, wherein the monool is initiatedwith a fatty alcohol.
 3. The polyol composition of claim 2, wherein themonool is initiated with a fatty hydrocarbon comprising a C₁₂ -C₁₅ fattyalcohol.
 4. The polyol composition of claim 3, wherein the numberaverage molecular weight of the monool is 1000 or less, exclusive of theinitiator.
 5. The polyol composition of claim 4, wherein the numberaverage molecular weight of the monool is 800 or less, exclusive of theinitiator.
 6. The polyol composition of claim 5, wherein the monool is aheteric polyoxyethylene-polyoxypropylene polyether monool.
 7. The polyolcomposition of claim 5, wherein the monool comprises an internal blockof polyoxyethylene units and a terminal block of polyoxypropylene units.8. The polyol composition of claim 5, wherein the C₄ -C₇ hydrocarboncomprises n-pentane, isopentane, or mixtures thereof.
 9. The polyolcomposition of claim 5, wherein the a) compound comprises a polyolhaving a number average molecular weight of 400 or more.
 10. The polyolcomposition of claim 9, wherein the a) compound comprises a polyesterpolyol having a number average molecular weight of 400 or more.
 11. Thepolyol composition of claim 10, further comprising water.
 12. The polyolcomposition of claim 1, wherein the fatty hydrocarbon initiatorcomprises a C₈ -C₂₄ fatty alcohol, said initiator reacted with a totalaverage of 2-20 moles of an alkylene oxide.
 13. The polyol compositionof claim 12, wherein said alkylene oxide comprises ethylene oxide,propylene oxide, or mixtures thereof.
 14. The polyol composition ofclaim 13, wherein the monool has a number average molecular weight of1000 or less.
 15. The polyol composition of claim 14, wherein the fattyhydrocarbon initiator comprises C₁₂ -C₁₅ fatty alcohols.
 16. The polyolcomposition of claim 15, wherein ethylene oxide and propylene oxide arerandomly added onto the C₁₂ -C₁₅ fatty alcohols and onto each other. 17.The polyol composition of claim 12, wherein the total average number ofmoles of alkylene oxide is from 6 to
 15. 18. The polyol composition ofclaim 15, wherein the C₄ -C₇ hydrocarbon blowing agent comprisesn-pentane, isopentane, cyclopentane, or mixtures thereof, and the a)compound comprises a polyester polyol having a number average molecularweight of 400 or more.
 19. The polyol composition of claim 1, whereinthe a) compound comprises a polyester polyol having a number averagemolecular weight of 400 or more, and the C₄ -C₇ hydrocarbon blowingagent comprises n-pentane, isopentane, cyclopentane, or mixturesthereof.
 20. The polyol composition of claim 19, comprising anemulsified polyol composition, wherein the amount of the monool iseffective to emulsify the blowing agent in the polyester polyol.
 21. Thepolyol composition of claim 1, comprising an emulsified polyolcomposition comprising:a) a polyester polyol having a number averagemolecular weight of 400 or more; b) 10 php to 35 php of a blowing agentcomprising n-pentane, isopentane, cyclopentane, or mixtures thereof; andc) an amount of monool effective to emulsify the blowing agent in thepolyester polyol for a period of at least 30 minutes.
 22. The polyolcomposition of claim 21, wherein the amount of blowing agent comprises22 php-28 php.
 23. The polyol composition of claim 21, wherein theamount of monool ranges from 6 php-12 php.
 24. The polyol composition ofclaim 21, wherein the polyester polyol comprises terephthalic acid,dimethyl terephthalate, polyethylene terephthalate, phthalic acid,isophthalic acid, phthalic anhydride, and/or by-products from themanufacture thereof, based polyester polyols.
 25. The polyol compositionof claim 1, wherein said emulsified polyol composition is reacted withan organic polyisocyanate compound.
 26. The polyol composition of claim25, further comprising an isocyanurate promoting catalyst.